Name the segment that is parallel to the

What number must be added to the expression below to complete the square? X^2+5x

Leno4ka [110]

Answer:

25/4

Step-by-step explanation:

x^2 +5x

To complete the square we take (b/2)^2

b =5

(5/2)^2

25/4

7 0

3 years ago

Read 2 more answers

I don't understand how to solve this pls help

Charra [1.4K]

the sine function is a many-to-one function and therefore has no inverse function.

However if the domain is restricted to -90° ≤ x ≤ 90°

Then the function is one-to-one for this domain

Thus, $sin^{-1}$ x is defined as the angle such that - π/2 ≤ x ≤ π/2

5π/6 is therefore outwith the domain

7 0

3 years ago

Confidence Interval Mistakes and Misunderstandingsâ€”Suppose that 500 randomly selected recent graduates of a university were as

kvv77 [185]

Answer:

The correct 95% confidence interval is (8.4, 8.8).

Step-by-step explanation:

The information provided is:

$n=500\\\bar x=8.6\\\sigma=2.2$

(a)

The (1 - α)% confidence interval for population mean (μ) is:

$CI=\bar x\pm z_{\alpha/2}\times \frac{\sigma}{\sqrt{n}}$

The 95% confidence interval for the average satisfaction score is computed as:

8.6 ± 1.96 (2.2)

This confidence interval is incorrect.

Because the critical value is multiplied directly by the standard deviation.

The correct interval is:

$8.6\pm 1.96 (\frac{2.2}{\sqrt{500}})=8.6\pm 0.20=(8.4,\ 8.6)$

(b)

The (1 - α)% confidence interval for the parameter implies that there is (1 - α)% confidence or certainty that the true parameter value is contained in the interval.

The 95% confidence interval for the mean rating, (8.4, 8.8) implies that the true there is a 95% confidence that the true parameter value is contained in this interval.

The mistake is that the student concluded that the sample mean is contained in between the interval. This is incorrect because the population is predicted to be contained in the interval.

(c)

The (1 - α)% confidence interval for population parameter implies that there is a (1 - α) probability that the true value of the parameter is included in the interval.

The 95% confidence interval for the mean rating, (8.4, 8.8) implies that the true mean satisfaction score is contained between 8.4 and 8.8 with probability 0.95 or 95%.

Thus, the students is not making any misinterpretation.

(d)

According to the Central Limit Theorem if we have a population with mean μ and standard deviation σ and we take appropriately huge random samples (n ≥ 30) from the population with replacement, then the distribution of the sample mean will be approximately normally distributed.

In this case the sample size is,

n = 500 > 30

Thus, a Normal distribution can be applied to approximate the distribution of the alumni ratings.

7 0

3 years ago

An educational psychologist wishes to know the mean number of words a third grader can read per minute.

Rama09 [41]

Answer: 208.

Step-by-step explanation:

The formula to find the minimum sample size is given by :-

$n= (\dfrac{z^*\times \sigma}{E})^2$ (1)

, where z* = critical z-value (two tailed).

$\sigma$ = Standard deviation ( from prior study ) and E = Margin of error.

As per given , we have

Margin of error : E= 0.29

Confidence level = 85%

Significance level = $\alpha=1-0.85=0.15$

Using z-table , the critical value (two -tailed)= $z^*=z_{\alpha/2}=z_{0.15/2}=z_{0.075}=1.439$

As per previous study , Variance = $\sigma^2=8.41$

$\sigma=\sqrt{8.41}=2.9$

Now, the required minimum sample size = $n= (\dfrac{(1.439)\times (2.9)}{0.29})^2$ [Substitute the values in formula (1)]

$n=(14.39)^2$

$n=207.0721\approx208$ [ Round to the next integer]

Hence, the minimum number of third graders that must be included in a sample = 208.

5 0

3 years ago

Solve the following quadratic by factoring.

Lina20 [59]

Answer:

4, -1

Step-by-step explanation:

We can reverse the FOIL (First, outside, inside, last) method to break down the equation. The question is asking to solve by factoring so you want to find the right combination of numbers this equation can be broken down into:

x^2 - 3x - 4 = 0

Because we want x squared, x needs to be multiplied by itself, so we can put x in the first slot for each.

(x + or - ?) ( x + or - ?) = 0

Then we need to find numbers that could be added to get -3 and multiplied to get -4. The only set of numbers that works for this is -4 and 1. Note that the sign you put in front of each number has an impact on your answers. With this we get:

(x - 4) (x + 1) = 0

To test that this is equal to the original equation, simply multiply it out using FOIL.

x * x = x^2

x * 1 = x

x * -4 = -4x

-4 * 1 = -4

Putting each component into an equation:

x^2 + x - 4x - 4 = 0

Simplifying:

x^2 - 3x - 4 = 0

Once we are sure it is still the same equation, we find the solutions. We know 0 multiplied by anything equals 0, so to get 0 as the answer, one of the sets in the parentheses must equal 0. (It doesn't matter what the other one is as long is one equals 0)

Therefore, we have 2 solutions, 4, and -1 because if x is 4, 4-4 is 0 which solves the equation, and if x is -1, then -1 + 1 is 0 which also solves the equation.

You can also check your answers by plugging them back into the original equation.

5 0

3 years ago